It is conventional practice in the molding of concrete blocks and the like to close the open bottom of a block mold by means of a pallet, introduce moldable material into the mold through its top, lower a stripper head into the mold, vibrate the mold to compact the material as the stripper head moves downwardly until the height of the molded block has been established, and then move the pallet support and the stripper head downwardly in unison to strip the molded block from the mold. The palletized block then is transferred from the pallet support to a conveyor or the like for delivery elsewhere, and the process then repeated for the production of additional blocks.
The operation of block molding machinery has been accompanied in the past by the generation of considerable noise. The generation of noise in the molding of blocks has been reduced substantially by fairly recent developments of the kind disclosed in the above mentioned application Ser. No. 713,920. Such apparatus achieves noise reduction by elevating the mold off the machine frame and clamping the pallet against the mold during its vibration by cushioned clamping means. It thus is possible to vibrate the mold and the pallet in unison without relative movement therebetween, thereby minimizing considerably the generation of noise.
To assure adequate control over the height of molded blocks it is preferred that the stripper head move into engagement with the moldable material during the vibration of the mold. As the material is compacted, the stripper head must move downwardly if it is to remain in contact with the material. This necessitates downward driving movement of the stripper head by suitable means, such as a cam controlled linkage. Since the mold vibrates, however, the linkage must absorb or compensate for the vibration of the stripper head caused by its engagement with the material in the mold. Such absorption or compensation results in the generation of noise.
A principal object of this invention is to provide concrete block making machinery and methods wherein the noise reduction associated with machinery of the kind disclosed in the aforementioned application can be retained and, in addition, substantial reduction of noise generated by the stripper head and its associated parts is achieved.